projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* memcpy.S: optimised assembly memcpy |
| 2 | * | |
| 3 | * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved. | |
| 4 | * Written by David Howells (dhowells@redhat.com) | |
| 5 | * | |
| 6 | * This program is free software; you can redistribute it and/or | |
| 7 | * modify it under the terms of the GNU General Public License | |
| 8 | * as published by the Free Software Foundation; either version | |
| 9 | * 2 of the License, or (at your option) any later version. | |
| 10 | */ | |
| 11 | ||
| 12 | ||
| 13 | .text | |
| 14 | .p2align 4 | |
| 15 | ||
| 16 | ############################################################################### | |
| 17 | # | |
| 18 | # void *memcpy(void *to, const char *from, size_t count) | |
| 19 | # | |
| 20 | # - NOTE: must not use any stack. exception detection performs function return | |
| 21 | # to caller's fixup routine, aborting the remainder of the copy | |
| 22 | # | |
| 23 | ############################################################################### | |
| 24 | .globl memcpy,__memcpy_end | |
| 25 | .type memcpy,@function | |
| 26 | memcpy: | |
| 27 | or.p gr8,gr9,gr4 | |
| 28 | orcc gr10,gr0,gr0,icc3 | |
| 29 | or.p gr10,gr4,gr4 | |
| 30 | beqlr icc3,#0 | |
| 31 | ||
| 32 | # optimise based on best common alignment for to, from & count | |
| 33 | andicc.p gr4,#0x0f,gr0,icc0 | |
| 34 | setlos #8,gr11 | |
| 35 | andicc.p gr4,#0x07,gr0,icc1 | |
| 36 | beq icc0,#0,memcpy_16 | |
| 37 | andicc.p gr4,#0x03,gr0,icc0 | |
| 38 | beq icc1,#0,memcpy_8 | |
| 39 | andicc.p gr4,#0x01,gr0,icc1 | |
| 40 | beq icc0,#0,memcpy_4 | |
| 41 | setlos.p #1,gr11 | |
| 42 | beq icc1,#0,memcpy_2 | |
| 43 | ||
| 44 | # do byte by byte copy | |
| 45 | sub.p gr8,gr11,gr3 | |
| 46 | sub gr9,gr11,gr9 | |
| 47 | 0: ldubu.p @(gr9,gr11),gr4 | |
| 48 | subicc gr10,#1,gr10,icc0 | |
| 49 | stbu.p gr4,@(gr3,gr11) | |
| 50 | bne icc0,#2,0b | |
| 51 | bralr | |
| 52 | ||
| 53 | # do halfword by halfword copy | |
| 54 | memcpy_2: | |
| 55 | setlos #2,gr11 | |
| 56 | sub.p gr8,gr11,gr3 | |
| 57 | sub gr9,gr11,gr9 | |
| 58 | 0: lduhu.p @(gr9,gr11),gr4 | |
| 59 | subicc gr10,#2,gr10,icc0 | |
| 60 | sthu.p gr4,@(gr3,gr11) | |
| 61 | bne icc0,#2,0b | |
| 62 | bralr | |
| 63 | ||
| 64 | # do word by word copy | |
| 65 | memcpy_4: | |
| 66 | setlos #4,gr11 | |
| 67 | sub.p gr8,gr11,gr3 | |
| 68 | sub gr9,gr11,gr9 | |
| 69 | 0: ldu.p @(gr9,gr11),gr4 | |
| 70 | subicc gr10,#4,gr10,icc0 | |
| 71 | stu.p gr4,@(gr3,gr11) | |
| 72 | bne icc0,#2,0b | |
| 73 | bralr | |
| 74 | ||
| 75 | # do double-word by double-word copy | |
| 76 | memcpy_8: | |
| 77 | sub.p gr8,gr11,gr3 | |
| 78 | sub gr9,gr11,gr9 | |
| 79 | 0: lddu.p @(gr9,gr11),gr4 | |
| 80 | subicc gr10,#8,gr10,icc0 | |
| 81 | stdu.p gr4,@(gr3,gr11) | |
| 82 | bne icc0,#2,0b | |
| 83 | bralr | |
| 84 | ||
| 85 | # do quad-word by quad-word copy | |
| 86 | memcpy_16: | |
| 87 | sub.p gr8,gr11,gr3 | |
| 88 | sub gr9,gr11,gr9 | |
| 89 | 0: lddu @(gr9,gr11),gr4 | |
| 90 | lddu.p @(gr9,gr11),gr6 | |
| 91 | subicc gr10,#16,gr10,icc0 | |
| 92 | stdu gr4,@(gr3,gr11) | |
| 93 | stdu.p gr6,@(gr3,gr11) | |
| 94 | bne icc0,#2,0b | |
| 95 | bralr | |
| 96 | __memcpy_end: | |
| 97 | ||
| 98 | .size memcpy, __memcpy_end-memcpy | |
| 99 | ||
| 100 | ############################################################################### | |
| 101 | # | |
| 102 | # copy to/from userspace | |
| 103 | # - return the number of bytes that could not be copied (0 on complete success) | |
| 104 | # | |
| 105 | # long __memcpy_user(void *dst, const void *src, size_t count) | |
| 106 | # | |
| 107 | ############################################################################### | |
| 108 | .globl __memcpy_user, __memcpy_user_error_lr, __memcpy_user_error_handler | |
| 109 | .type __memcpy_user,@function | |
| 110 | __memcpy_user: | |
| 111 | movsg lr,gr7 | |
| 112 | subi.p sp,#8,sp | |
| 113 | add gr8,gr10,gr6 ; calculate expected end address | |
| 114 | stdi gr6,@(sp,#0) | |
| 115 | ||
| 116 | # abuse memcpy to do the dirty work | |
| 117 | call memcpy | |
| 118 | __memcpy_user_error_lr: | |
| 119 | ldi.p @(sp,#4),gr7 | |
| 120 | setlos #0,gr8 | |
| 121 | jmpl.p @(gr7,gr0) | |
| 122 | addi sp,#8,sp | |
| 123 | ||
| 124 | # deal any exception generated by memcpy | |
| 125 | # GR8 - memcpy's current dest address | |
| 126 | # GR11 - memset's step value (index register for store insns) | |
| 127 | __memcpy_user_error_handler: | |
| 128 | lddi.p @(sp,#0),gr4 ; load GR4 with dst+count, GR5 with ret addr | |
| 129 | add gr11,gr3,gr7 | |
| 130 | sub.p gr4,gr7,gr8 | |
| 131 | ||
| 132 | addi sp,#8,sp | |
| 133 | jmpl @(gr5,gr0) | |
| 134 | ||
| 135 | .size __memcpy_user, .-__memcpy_user |